A new development in applying protective, decorative coatings or paints to surfaces such as automobile panels, household appliances and the like involves coating a water based polyurethane paint on a stretchable carrier film which is stretched over and bonded to the surface to be covered. Such paint-coated sheets afford savings in paints as compared with conventional spray painting processes. Moreover, air pollution from evaporating paint solvents can be reduced.
In order to improve the adhesion of paint layers to the stretchable carrier film, compositions have been developed to serve as adhesion promoting layers or tie coats. While some of these improve adhesion, they create other problems such as curling of the carrier film, yellowing of layers of the finished article, and/or defects in the ultimate paint coating, which are caused by craters or pinholes in the tie coat (also referred to as "repellencies" in the photographic industry.) Further improvement in tie coat compositions for adhering aqueous polyurethane paints to carrier films has, therefore, been desirable.